Long-Term Debt (Details) (USD $)	12 Months Ended		0 Months Ended	12 Months Ended		12 Months Ended							0 Months Ended
	Dec. 31, 2013	Dec. 31, 2013 Minimum	May 29, 2013 Convertible Senior Notes Due 2020	Dec. 31, 2013 Convertible Senior Notes Due 2020	May 21, 2013 Convertible Senior Notes Due 2020	Dec. 31, 2013 Convertible Senior Notes Due 2020 Additional Paid-In Capital	Dec. 31, 2013 Convertible Senior Notes Due 2020 Non-current assets	Dec. 31, 2013 Senior Secured Notes Due 2018	Dec. 31, 2013 Senior Secured Notes Due 2018 Purchase of a debt-like instrument from BioPharma	Mar. 25, 2013 Senior Secured Notes Due 2018 Purchase of a debt-like instrument from BioPharma	Mar. 25, 2013 Senior Secured Notes Due 2018 Purchase of a debt-like instrument from BioPharma Minimum	Mar. 25, 2013 Senior Secured Notes Due 2018 Purchase of a debt-like instrument from BioPharma Maximum	Apr. 09, 2013 Senior Secured Notes Due 2018 Purchase of a debt-like instrument from BioPharma Initial closing	Mar. 25, 2013 Senior Secured Notes Due 2018 Purchase of a debt-like instrument from BioPharma Secondary closing
Long-term debt
Amount of offering			$ 30,000,000		$ 220,000,000
Interest rate (as a percent)					4.50%
Net proceeds from offering	290,247,000		241,800,000										48,400,000
Shares of common stock into which debt is convertible				16,826,000
Conversion rate in proportion to principal amount of Convertible Notes				0.0673038
Conversion price per share (in dollars per share)				$ 14.858
Initial fair value of the liability component	204,737,000			154,737,000	154,700,000
Carrying value of the equity component					95,300,000
Debt issuance costs				8,200,000		3,100,000	5,100,000	1,600,000
Total interest expense recognized				14,300,000
Amortization of debt discount				8,400,000
Amortization of deferred financing costs				444,000					329,000
Remaining expected life				4 years 10 months 24 days
Cap price of capped call transactions (in dollars per share)		$ 20		$ 20
Fair value of capped calls				34,700,000
Amount received													50,000,000
Amount received in funding and facility payments													500,000
Additional discretionary amount receivable														60,000,000
Additional discretionary amount receivable in funding and facility payments														600,000
Amount of reasonable and documented out-of-pocket legal costs and fees for which entity is responsible												300,000
Scheduled quarterly payment amount as a percentage of net sales											25.00%
Amount due as a percentage of net sales, if scheduled quarterly payments are less than 25% of the net sales										25.00%
Make-whole premium ratio										1.03
Annual implied effective interest rate (as a percent)				15.20%					13.38%
Imputed interest									$ 5,200,000